Pulmonary delivery of active fragments of parathyroid hormone

ABSTRACT

Systemic delivery of parathyroid hormone to a mammalian host is accomplished by inhalation through the mouth of a dispersion of an N-terminal fragment of PTH. It has been found that such respiratory delivery of the PTH fragment provides a pulsatile concentration profile of the PTH in the host&#39;s serum. PTH fragment compositions include dry powder formulations having the PTH present in a dry bulking powder, liquid solutions or suspensions suitable for nebulization, and aerosol propellants suitable for use in a metered dose inhaler.

This is a continuation of application Ser. No. 08/232,849 filed Apr. 25,1994,now U.S. Pat. No. 5,607,915 which is a FWC Continuation ofapplication Ser. No. 07/953,397 filed Sep. 29, 1992, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to methods and compositions forsystemic administration of parathyroid hormone to mammalian hosts. Moreparticularly, the present invention relates to pulmonary administrationof active parathyroid hormone fragments to provide pulsatile serumconcentration profiles.

Human parathyroid hormone (PTH) is an 84 amino acid protein that isinvolved in calcium and phosphorus homeostasis and control of bonegrowth and density. N- terminal fragments of PTH, particularly thoseconsisting of amino acids 1-34 and 1-38, retain the full biologicalactivity of the intact protein. Recently, the use of PTH and PTHfragments in combination with vitamin D or dietary calcium was found tobe effective in the treatment of osteoporosis when administered to ahost on a periodic, preferably daily, basis.

Heretofore, the administration of PTH and PTH fragments has generallybeen accomplished subcutaneously, i.e., through injection. The need toinject PTH (or any other drug) on a daily basis, however, isundesirable. Most patients have an aversion to self-injection of drugs,and the need to visit a clinic or doctor's office for administration isinconvenient and burdensome. While other forms of administration havebeen suggested, such as oral delivery to the stomach, transdermaldelivery, and nasopharyngeal absorption, none of these delivery routeshas been proven to be effective and each suffers from certain drawbacks.Oral delivery results in very low bioavailability of polypeptide drugs,usually below 1%, due to degradation in the gastrointestinal tract.Moreover, the epithelial lining of the gastrointestinal tract isimpermeable to most polypeptides. Nasopharyngeal and transdermaldelivery avoid the problems of enzyme degradation, but usually requirepenetration enhancers in order to effect systemic absorption. Even withsuch penetration enhancers, bioavailability will usually be very low,and the penetration enhancers can often cause undesirable irritation. Inthe case of nasopharyngeal administration, penetration enhancers canoften damage the nasal epithelium and chronic use has been associatedwith hyperplasia of the nasal lining.

Pulmonary or respiratory delivery of polypeptide drugs has also beensuggested. Relatively large proteins, such as growth factors andcytokines which are typically larger than 150 amino acids, are oftenreadily absorbed through the cellular lining of the alveolar region ofthe mammalian lung. Advantageously, such absorption can be achievedwithout the use of penetration enhancers. The pulmonary absorption ofsmaller proteins, usually below 100 amino acids in length, is much lesspredictable. Many smaller native polypeptides are not absorbed by themammalian lung, but certain examples such as insulin (51 amino acids)and calcitonin (32 amino acids) have been found to be systemicallyabsorbed when delivered to the lung. Even when a protein drug issystemically absorbed by a host through the lung, the pharmacologicalkinetics of the drug are unpredictable. Thus, both the amount and timingof drug bioavailability are unpredictable.

It is presently believed that PTH is most effectively delivered to apatient in a pulsatile fashion. That is, serum concentrations of PTHshould rise rapidly after administration and fall rapidly after a peakhas been reached, generally resulting in a spike in the serumconcentration profile. Thus, it is advantageous for any route of PTHdelivery to provide such a serum concentration profile.

For these reasons, it would be desirable to provide alternative deliverymethods for parathyroid hormone which are patient acceptable. Suchmethods should avoid subcutaneous injection, limit irritation to theskin and body mucosa, and provide a desired pulsatile delivery profilediscussed above. Such methods should further provide for high levels ofPTH bioavailability, be amenable to self-administration by the patient,and be economic.

2. Description of the Background Art

U.S. Pat. Nos. 4,833,125 and 4,698,328, describe the administration ofactive parathyroid hormone fragments in combination with vitamin D or adietary calcium supplement. Suggested administration routes includeparenteral by injection, rapid infusion, nasopharyngeal absorption,dermal absorption, or oral. See also, Neer et al. (1987) Osteoporosis53:829-835. U.S. Pat. No. 5,011,678, describes the use of amphophilicsteroids as a penetration enhancer for nasal or bronchopulmonarydelivery of proteins and polypeptides, listing parathyroid hormone asone of a "veritable host" of proteins which could be delivered with theenhancer. Parathyroid hormone (full length) is secreted naturally fromthe parathyroid gland as a series of spikes in a pulsatile fashion whichis analogous to pituitary hormones (Harms et al. (1987) Int. Symp. onOsteoporosis, Aalborg, Abstract 232). The full length hormone is rapidlybroken down in the circulation to several fragments which are thedominant serum forms. It is hypothesized that an intermittent orpulsatile secretion pattern for parathyroid hormone is necessary tomaintain its bone restoring properties (Hesch et al. (1988) Calcif.Tissue Int. 42:341-344 and Habener et al. (1971) Proc. Natl. Acad. Sci.USA 68:2986-2991). Patton and Platz (1992) Adv. Drug Deliver. Rev.8:179-196. describe methods for delivering proteins and polypeptides byinhalation through the deep lung.

SUMMARY OF THE INVENTION

According to the present invention, methods and compositions for thesystemic delivery of parathyroid hormone (PTH) to a mammalian host,particularly a human patient suffering from or at risk of osteoporosis,provide for a preferred pulsatile concentration profile of the PTH inthe host's serum after administration. In particular, the methods of thepresent invention rely on pulmonary or respiratory delivery of abiologically active N-terminal fragment of PTH, where delivery of thefragment through the alveolar region of the lung results in a rapidconcentration spike of PTH in the host serum followed by a quickdecrease in concentration. Surprisingly, pulmonary delivery of intactPTH protein under the same conditions will result in a relativelyconstant serum concentration of PTH over an extended time period. Theability to obtain the desired pulsatile serum concentration profile bypulmonary delivery of the PTH fragments, in contrast to the delivery ofintact PTH, could not have been predicted with any degree of certaintyprior to the work reported herein.

According to an exemplary embodiment, the method of the presentinvention comprises dispersing a preselected amount of the PTH fragmentin a volume of gas to produce an aerosolized bolus. The PTH fragmentusually consists of the N-terminal 34 or 38 amino acids of the PTHmolecule (but may be an N-terminal fragment of any size which displaysthe desired pharmacokinetic profile, usually being 50 or fewer aminoacids), and the dispersion may be produced by introducing a dry powderof the fragment into a high velocity gas stream, by nebulizing a liquidsolution or suspension of the fragment, or by releasing a propellantcontaining the PTH fragment through a nozzle. The patient then inhalesthe aerosolized bolus through the mouth and into the alveolar region ofthe lungs. By repeating the dispersing and inhaling steps a sufficientnumber of times, a desired total dosage of the PTH fragment can bedelivered to the patient.

Pharmaceutical compositions according to the present invention includedry powder formulations where the PTH fragment is present as a powderhaving a mean particle size in the range from 0.5 μm to 5 μm in apharmaceutically acceptable dry bulking powder, where the PTH is presentat from 1% to 10%. A pharmaceutical composition suitable fornebulization comprises the biologically active fragment of PTH presentin an aqueous buffer at pH 4-6 in a concentration in the range from 1mg/ml to 20 mg/ml. Pharmaceutical compositions suitable for propellantdispersion comprise a powder of the PTH having a mean particle size inthe range from 0.5 μm to 5 μm present in an aerosol propellant.

In addition to the preferred pulsatile pharmacokinetic serum profile ofthe PTH fragments, the methods and compositions of the present inventionprovide a high level of patient acceptability. PTH administration doesnot require injection and can be self-administered by the patient on adaily basis, usually without complications such as those associated withtransdermal and intranasal delivery. The methods and compositions of thepresent invention also provide for a high level bioavailability of thePTH, and are economic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph illustrating the serum profile over time of PTH34administered intravenously and intratracheally to rats, as described indetail in the Experimental section hereinafter.

FIG. 2 is a graph illustrating the serum profile of PTH84 administeredintravenously and intratracheally to rats, as described in detail in theExperimental section hereinafter.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Parathyroid hormone (PTH) is delivered to a mammalian host by inhalationinto the alveolar region of the host's lungs. The cellular lining of thedeep mammalian lung is extremely thin (0.1 μm) and has been found to benaturally permeable to both full length PTH and certain biologicallyactive and N-terminal fragments of PTH, as described below.Surprisingly, however, such pulmonary or respiratory delivery of the PTHfragments only (and not the full length PTH) has been found to provide adesired pulsatile serum concentration profile of the PTH, as is believedto enhance the biological activity of the PTH, particularly whentreating osteoporosis.

Thus, the present invention provides for the pulmonary or respiratorydelivery of biologically active N-terminal fragments of PTH byinhalation by a patient through the mouth, where such fragments have asize which is less than that of full size native human PTH (human PTH is84 amino acids) and which results in a pulsatile serum concentrationprofile characterized by a rapid rise to a peak and followed by a rapidfall. The PTH fragments will preferably be fragments of human PTH (orrecombinantly produced polypeptides having the sequence of human PTH),typically including up to about 50 amino acids from the N-terminus ofthe PTH molecule, more preferably consisting of either amino acids 1-34or amino acids 1-38 of human PTH, as set forth in Table 1 below.

Useful biologically active fragments of PTH also include chemicallymodified parathyroid hormone fragments which retain the activityassociated with parathyroid hormone. The necessary activity is thestimulation of bone formation. Modifications that may be consideredinclude:

(1) PTH fragments with carboxyl amino acid extensions beyond position 34(but usually not beyond position 50) of the human PTH molecule, oraminoterminal extensions, or amino acid substitutions that produce otherdesirable features, such as an alpha-carboxyl amide at the carboxylterminus. A desirable modification would enhance activity in vivo.

(2) PTH fragments extended to include amino acids 1-38, which wouldenhance receptor binding and hence the activity per mole.

(3) PTH fragments chemically modified so as to enhance throughabsorption through the alveolar region of the lung.

(4) Physiologically acceptable salts and esters of PTH fragments.

A PTH fragment obtainable from a mammal is generally preferred overother types of parathyroid hormone fragments, such as derivatives. Useof a PTH fragment consisting of the first thirty-four amino acidresidues of human parathyroid hormone (hereafter abbreviated "PTH34") isespecially preferred for use in humans. Other preferred PTH fragmentsare those which display some or all of the following desirable features:increased potency with regard to the necessary activity, increased easeof administration, increased selectivity to decrease potential sideeffects, and decreased antigenicity in humans to avoid an adverse immuneresponse. PTH fragments molecules having the sequences 1-34 or 1-38 ofTable 1 SEQ. ID NO: 1!are particularly preferred:

                  TABLE 1                                                         ______________________________________                                         ##STR1##                                                                      ##STR2##                                                                      ##STR3##                                                                      ##STR4##                                                                     ______________________________________                                    

The preferred PTH34 and PTH38 fragments may be obtained commerciallyfrom suppliers such as Peninsula Laboratories, Inc., Belmont, Calif.;Sigma Chemical Co., St. Louis, Mo.; Bachem California, Torrance, Calif.;and others. Alternatively, the PTH fragments may be producedrecombinantly by expression in cultured cells of recombinant DNAmolecules encoding the desired fragment of the PTH molecule. Suitablerecombinant expression systems and methods are well described in theliterature. See, for example, Manniatis, Molecular Cloning: A LaboratoryManual, Cold Spring Harbor, N.Y., 1982. The DNA molecules which areexpressed may themselves be synthetic or derived from a natural source.Synthetic polynucleotides may be synthesized by well-known techniques,for example, single-stranded DNA fragments may be prepared by thephosphoraminite method first described by Beaucage and Carruthers (1981)Tett. Lett. 22:1859-1862. A double-stranded fragment may then beobtained either by synthesizing the complementary strand and annealingthe strands together under appropriate conditions, or by adding thecomplementary strand using DNA polymerase with an appropriate primersequence. The preparation of synthetic DNA sequences is convenientlyaccomplished using automated equipment available from suppliers, such asApplied Biosystems, Inc., Foster City, California.

The PTH fragments will be formulated in pharmaceutically acceptablecompositions suitable for pulmonary or respiratory delivery to amammalian host, usually a human host at risk of or suffering fromosteoporosis. Particular formulations include dry powders, liquidsolutions or suspensions suitable for nebulization, and propellantformulations suitable for use in metered dose inhalers (MDI's). Thepreparation of such formulations is well described in the patent,scientific, and medical literatures, and the following descriptions areintended to be exemplary only.

Dry powder formulations will typically comprise the PTH fragment in adry, usually lyophilized, form with a particle size within a preferredrange for deposition within the alveolar region of the lung, typicallyfrom 0.5 μm to 5 μm. Respirable powders of PTH fragments within thepreferred size range can be produced by a variety of conventionaltechniques, such as jet-milling, spray-drying, solvent precipitation,and the like. Dry powders can then be administered to the patient inconventional dry powder inhalers (DPI's) that use the patient'sinspiratory breath through the device to disperse the powder or inair-assisted devices that use an external power source to disperse thepowder into an aerosol cloud. A particularly useful dry powder disperseris described in copending application Ser. No. 07/910,048, assigned tothe assignee of the present invention, the full disclosure of which isincorporated herein by reference.

Dry powder devices typically require a powder mass in the range fromabout 1 mg to 10 mg to produce a single aerosolized dose ("puff"). Sincethe required dose of PTH fragment will generally be much lower than thisamount, as discussed below, the PTH powder will typically be combinedwith a pharmaceutically acceptable dry bulking powder, with the PTHpresent usually at from about 1% to 10% by weight. Preferred dry bulkingpowders include sucrose, lactose, trehalose, human serum albumin (HSA),and glycine. Other suitable dry bulking powders include cellobiose,dextrans, maltotriose, pectin, sodium citrate, sodium ascorbate,mannitol, and the like.

Typically, suitable buffers and salts may be used to stabilize the PTHfragments in solution prior to particle formation. Suitable buffersinclude phosphate, citrate, acetate, and tris-HCl, typically atconcentrations from about 5 mM to 50 mM. Suitable salts include sodiumchloride, sodium carbonate, calcium chloride, and the like. Otheradditives, such as chelating agents, peptidase inhibitors, and the like,which would facilitate the biological activity of the PTH fragment onceit is dissolved within the lung would be appropriate. For example,ethylenediaminetetraacetic acid (ETDA) would be useful as a chelator fordivalent cations which are peptidase cofactors.

Liquid formulations of PTH fragments for use in nebulizer systems canemploy slightly acidic buffers (pH 4-6 ) with PTH concentrations of fromabout 1 mg/ml to 20 mg/ml. Suitable buffers include acetate, ascorbate,and citrate, at concentrations of 5 mM to 50 mM. These buffers can actas antioxidants, or other physiologically acceptable antioxidants can beadded to protect free methionines in the PTH fragment against oxidation.Other components may be added to enhance or maintain chemical stability,including chelating agents, protease inhibitors, isotonic modifiers,inert gases, and the like. A preferred type of nebulizer suitable fordelivering such liquid formulations is described in copendingapplication Ser. No. 07/910,048, the disclosure of which has previouslybeen incorporated herein by reference.

For use in MDI's, the PTH fragments of the present invention will bedissolved or suspended in a suitable aerosol propellant, such as achlorofluorocarbon (CFC) or a hydrofluorocarbon (HFC). Suitable CFC'sinclude trichloromonofluoromethane (propellant 11),dichlorotetrafluoromethane (propellant 114), and dichlorodifluoromethane(propellant 12). Suitable HFC's include tetrafluoroethane (HFC-134a) andheptafluoropropane (HFC-227).

Preferably, for incorporation into the aerosol propellant, the PTHfragments of the present invention will be processed into respirableparticles as described for the dry powder formulations. The particlesare then suspended in the propellant, typically being coated with asurfactant to enhance their dispersion. Suitable surfactants includeoleic acid, sorbitan trioleate, and various long chain diglycerides andphospholipids.

Such aerosol propellant formulations may further include a loweralcohol, such as ethanol (up to 30% by weight) and other additives tomaintain or enhance chemical stability and physiological acceptability.

Pulmonary or respiratory administration of PTH fragments according tothe present invention will be useful in the treatment of osteoporosis,where the PTH fragment will be administered in combination with vitaminD calcitonin, and/or dietary calcium supplements. Such treatment methodsare well described in U.S. Pat. Nos. 4,698,328 and 4,833,125, thedisclosures of which have previously been incorporated herein byreference.

The total aerosolized dosage of PTH fragment for the treatment ofosteoporosis will typically be in range from about 100 μg to 2,000 μgper day, usually being in the range from about 250 μg to 1000 μg perday. Such dosages will result in a total systemic availability (i.e.,amount which is delivered to the blood) in the range from about 50 μg to500 μg per day, usually from 100 μg to 250 μg, per day. Precise dosageswill, of course, vary depending on the activity of the particular PTHfragment or analog employed, and other known pharmacokinetic factors.Usually, the total dosage of PTH fragment will be delivered in aplurality of separate aerosolized doses, typically being at least twoand, often being from three to ten, where each aerosolized boluscontains from 50 μg to 500 μg of the PTH fragment.

Pulmonary delivery of PTH fragments according to the methods of thepresent invention has been found to provide a desired pulsatile serumconcentration profile. The pulsatile serum PTH fragment concentrationprofile will typically peak within 30 minutes after administration, withserum concentrations falling rapidly, typically to below 50% of maximumwithin 30 minutes of the peak and to below 25% within 60 minutes of thepeak.

In the case of a dry powder formulation, a sufficient amount of drybulking powder will be added so that a total dosage of PTH fragmentwithin the above range can be achieved with one or more aerosolizedboluses which are to be inhaled by the patient. Typically, the activePTH fragment will be present at from about 1% to 25% by weight of thepowder, with aerosolized boluses including from 1 mg to 10 mg of thepowder. Liquid formulations suitable for use in nebulizers typicallyhave a concentration of the PTH fragment in the range from about 1 mg/mlto 20 mg/ml, with the total volume of nebulized liquid needed to deliverthe bolus in the range from about 0.1 ml to 1 ml. The aerosol propellantformulations will be delivered by MDI at about 0.5 mg to 5 mg of PTHfragment per aerosol dose. Because of the inefficiencies of MDI devices,only a small portion, typically in the range of 5% to 20%, of the drugwill reach the lungs. Thus, a sufficient amount of the PTH fragment canbe delivered in from two to five aerosolized boluses, with about 1 mg ofthe PTH fragment in each of the boluses.

The following examples are offered by way of illustration, not by way oflimitation.

Experimental

Materials and Methods Recombinant human parathyroid hormone (PTH84) wasobtained from Peninsula Laboratories, Inc., Belmont, Calif. (Lot No.800929). A recombinant fragment (amino acids 1-34) of human parathyroidhormone (PTH34) was obtained from Sigma Chemical Co., St. Louis, Mo.(Lot No. 098F48052).

Rats (approximately 300-320 g) were obtained from Simonsone Labs,Gilroy, Calif.

PTH84 and PTH34 were administered to rats intravenously (IV) andintratracheally (IT) suspended in 100 μl of 20 mM citrate buffer, pH 5.Dosages were 5 μg for IV administration of PTH84, 100 μg for ITadministration of PTH84, 25 μg for IV administration of PTH34, and 100μg for IT administration of PTH34. IT administration was performed bymaking a one inch incision in the medial neck region and exposing thetrachea. The polypeptide suspensions were injected into the tracheausing a tuberculin syringe with a 30 gauge needle over approximately oneminute. The head of the rat was held upright during the intratrachealinjection and for one additional minute thereafter.

Rat serum was assayed for PTH34 at periodic intervals after PTH34administration using a Nichols Instrument INS PTH assay kit whichmeasures PTH34 with no cross-reactivity to PTH28-54, PTH44-68, andPTH53-84.Samples were diluted as necessary to obtain measurableconcentrations.

Rat serum was assayed for PTH84 with Nichols Instrument Alegro assay kitfor human PTH which measures PTH84 with no cross-reactivity with PTH34,PTH39-68, PTH44-68, PTH53-84, and PTH39-84. Samples were diluted asnecessary to obtain measurable concentrations.

Results The serum profiles of PTH34 and PTH84 in rats following IV andIT administration are shown in FIGS. 1 and 2, respectively. The absolutebioavailability of PTH34, which indicates the percentage of totaladministered hormone that got into the blood, was about 40%. Theabsorption profile of PTH34 exhibited a spike at 15 minutes withactivity diminishing rapidly thereafter. This is similar to the profileseen after subcutaneous injection. In contract, PTH84 at the sameintratracheal dose, exhibited a very different absorption profile.Instead of a spike, a plateau in serum levels occurred that did notdiminish significantly during the 90 minutes of the experiment. Thebioavailability of PTH84 at 90 minutes was about 23% (as measured by thetruncated area under the curve up to 90 minutes), but the slow sustainedrelease absorption profile suggests that serum levels would havepersisted for longer times.

Although the foregoing invention has been described in detail forpurposes of clarity of understanding, it will be obvious that certainmodifications may be practiced within the scope of the appended claims.

    __________________________________________________________________________    SEQUENCE LISTING                                                              (1) GENERAL INFORMATION:                                                      (iii) NUMBER OF SEQUENCES: 1                                                  (2) INFORMATION FOR SEQ ID NO:1:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 38 amino acids                                                    (B) TYPE: amino acid                                                          (C) STRANDEDNESS: single                                                      (D) TOPOLOGY: linear                                                          (ii) MOLECULE TYPE: peptide                                                   (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                                       SerValSerGluIleGlnLeuMetHisAsnLeuGlyLysHisLeuAsn                              151015                                                                        SerMetGluArgValGluTrpLeuArgLysLysLeuGlnAspValHis                              202530                                                                        AsnPheValAlaLeuGly                                                            35                                                                            __________________________________________________________________________

What is claimed is:
 1. A method for pulsatile systemic delivery of an N-terminal peptide fragment of parathyroid hormone (PTH) to a mammalian subject, said method comprising:inhalation through the mouth by the subject of a dispersion of an N-terminal peptide fragment of PTH consisting of the first 34 to 38 amino acids of SEO ID No. 1 resulting in deposition of the peptide fragment in the alveolar region of the lungs and a subsequent rapid rise followed by a rapid fall in the serum concentration of said peptide fragment.
 2. A method as in claim 1, wherein the total dosage of PTH fragment is in the range from 100 μg to 2,000 μg per day, resulting in systemic availability in the range from 50μg to 500 μg per day.
 3. A method as in claim 1, wherein the PTH fragment dispersion comprises a dry powder including a bulking agent.
 4. A method as in claim 1, wherein the PTH fragment dispersion comprises a nebulized liquid solution or suspension of the PTH fragment.
 5. A method as in claim 1, wherein the PTH fragment dispersion comprises a dry powder and an aerosol propellant.
 6. A method as in claim 1, further comprising administering vitamin D or dietary calcium to the host in order to treat osteoporosis.
 7. A method for pulsatile systemic delivery of an active fragment of parathyroid hormone (PTH) to a patient, said method comprising:(a) dispersing a preselected amount of a PTH fragment consisting of the first 34 to 38 amino acids of SEO ID No. 1 in a volume of gas to produce an aerosolized bolus; (b) inhaling of the aerosolized bolus by the patient through the mouth and into the alveolar region of the lungs; and repeating steps (a) and (b) a sufficient number of times until a desired total dosage of PTH fragment is delivered.
 8. A method as in claim, 7 wherein the aerosolized bolus contains from about 50 μg to 500 μg of PTH fragment and the total dosage is from about 100 μg to 2,000 μg per day, resulting in systemic availability in the range from 50 μg to 500 μg per day.
 9. A method as in claim 7, wherein the aerosolized bolus has a volume in the range from 10 ml to 750 ml.
 10. A method as in claim 7, wherein the PTH fragment is dispersed in an aerosol of particles in the size range from 0.5 μm to 5 μm.
 11. A method as in claim 7, wherein the PTH fragment comprises a dry powder present in a bulking agent, and dispersing comprises introducing the dry powder into a high velocity gas stream.
 12. A method as in claim 7, wherein the PTH fragment comprises a liquid solution or suspension, and dispersing comprises nebulization of the liquid.
 13. A method as in claim 7, wherein the PTH fragment comprises a liquid or powder present in a propellant, and dispersing comprises releasing the propellant through a nozzle to produce the dispersion.
 14. A method as in claim 7, further comprising administering vitamin D or dietary calcium to the patient in order to treat osteoporosis. 